Conjugate vaccines for N. meningitidis serogroup C have been approved for human use, and include the products known as Menjugate™ [1], Meningitec™ and NeisVac-C™. Bivalent mixtures of conjugates from serogroups A+C [2,3] and C+Y [4] have also been reported. Mixtures of conjugates from all four of serogroups A, C, W135 and Y are also known (e.g. see references 5-9), including the Menactra™ product that was licensed in 2005.
In addition to the antigens included in a vaccine, an important aspect of effective immunisation is the dosing schedule. As noted in chapter 8 of reference 10, “most vaccines require administration of multiple doses in a primary series for development of immunity”. Moreover. “periodic revaccination (‘booster doses’) with certain vaccines may be necessary to maintain immunity”.
Known schedules for serogroup C meningococcal conjugate vaccines include: a single dose at 12 months of age; two doses at 2 & 4 months; three doses at 2, 3 & 4 months of age; three doses at 2, 4 & 6 months of age; three doses at 3, 5 & 12 months of age; three doses at 2, 4 & 12 months. Alternative schedules, including the potential for a dose in late infancy or the second year of life, have been suggested [11].
Multivalent meningococcal conjugate combinations have been administered according to various dosing schedules. For example, known single-dose schedules for multivalent meningococcal conjugate vaccines include: at 14 weeks of age [12]; at 6 months of age [13]; at 9 months [12]; between 12-16 months [14]; between 2-3 years of age [5, 15]; between 2-10 years [16, 17, 18]; between 11-18 years [18]; 18-50 years [19]; 18-55 years [18]. The prescribing information for Menactra™ shows that it is administered as a single dose in 11-18 or 18-55 year olds.
Known 2-dose schedules for multivalent meningococcal conjugate vaccines include: 2 & 6 months of age [13]; first dose at 14 weeks of age, second dose at 9 months of age [12]; first dose at 12-15 months, second dose 2 months later [5]; first dose at 12-16 months, second dose 1 month later [14]; doses in 2 year olds at time zero and then 2 months later [18]; in adults at time zero and then 6 weeks later [2]; in adults at time zero and then 2 months later [3]. A clinical study has also been reported in which patients received a first dose aged 11-18 years and a second dose 3 years later.
Known 3-dose schedules for multivalent meningococcal conjugate vaccines include: 6, 10 and 14 weeks of age [5,12]; 2,3 & 4 months [13]; 2,4 & 6-months of age [18]; 3, 4 & 5 months of age [20].
A 4-dose schedule at 6 weeks, 10 weeks, 14 weeks and 9 months is disclosed in reference 12.
It is an object of the invention to provide further and improved schedules for administering multivalent meningococcal conjugate vaccines, in particular to children.